CMV causes sight- or life-threatening opportunistic infections in people with AIDS. Intravenous agents including ganciclovir, foscarnet, and cidofovir are presently approved as treatments for CMV retinitis within this population. Ganciclovir and foscarnet induction and maintenance therapy require daily infusions and usually require the use of long-term indwelling central venous catheters. Although the treatment interval of cidofovir is longer, administration necessitates the use of pre-hydration and probenecid in order to avoid a risk of renal toxicity. Oral ganciclovir is an alternative to the intravenous formulation for the maintenance treatment of CMV retinitis. However, because blood levels achieved after oral ganciclovir are low compared to intravenous, oral ganciclovir cannot be used for induction therapy. In an attempt to improve the bioavailability of ganciclovir, valganciclovir was developed. Valganciclovir is a ganciclovir prodrug which, when administered orally, is rapidly converted to the active compound ganciclovir during a first-pass process, with the majority of hydrolysis occurring pre-systemically. Studies have shown that valganciclovir tablets allow systemic exposure of ganciclovir comparable to that achieved with recommended doses of intravenous ganciclovir.